From patchwork Mon Oct 12 14:50:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mathieu Desnoyers X-Patchwork-Id: 288530 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C739FC433DF for ; Mon, 12 Oct 2020 14:50:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 88C7620838 for ; Mon, 12 Oct 2020 14:50:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=efficios.com header.i=@efficios.com header.b="Embw51+d" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389340AbgJLOue (ORCPT ); Mon, 12 Oct 2020 10:50:34 -0400 Received: from mail.efficios.com ([167.114.26.124]:60676 "EHLO mail.efficios.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2389179AbgJLOuc (ORCPT ); Mon, 12 Oct 2020 10:50:32 -0400 Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 43BF62EA05B; Mon, 12 Oct 2020 10:50:31 -0400 (EDT) Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id Lmg4qct2joTX; Mon, 12 Oct 2020 10:50:31 -0400 (EDT) Received: from localhost (localhost [127.0.0.1]) by mail.efficios.com (Postfix) with ESMTP id 8002E2EA058; Mon, 12 Oct 2020 10:50:30 -0400 (EDT) DKIM-Filter: OpenDKIM Filter v2.10.3 mail.efficios.com 8002E2EA058 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=efficios.com; s=default; t=1602514230; bh=gUVxy+w1j0BD9TTwQVdU1mJ9SdqfH2wgwt1qmAnsPt4=; h=From:To:Date:Message-Id; b=Embw51+dOdb2Igu9ZehQVbkEQ3iZ8QtXU81m2uLnDFH0sjK3rr1Y7przzOzl2YHZp 3nW+Ql47ymo5Hk73T68fW+5PQwFmJVeyFiBSL/0hfx5YW4tN2nl85I0Nta818LGwXo yOVkw8//IjKh5ZC6cy6nl9dyR9GndqSY6SaW8mECV4BihDlsm/5Ei4JpkzvPo4NKrz HoucjgECkfCeyC75PZkiLNWOSVCFZ04tCZb0PZQ1bIrQJ6a3YTcnquzEtfwPFhNH4i HbW+wUtXbNGxMVfnCGDSPHfdtfddjxbVbW+4qt14LwjFCCEj9wE49zJ4xafzb1G6xB gUwpXGsVaweXw== X-Virus-Scanned: amavisd-new at efficios.com Received: from mail.efficios.com ([127.0.0.1]) by localhost (mail03.efficios.com [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id g9Ewr83L4DrT; Mon, 12 Oct 2020 10:50:30 -0400 (EDT) Received: from localhost.localdomain (192-222-181-218.qc.cable.ebox.net [192.222.181.218]) by mail.efficios.com (Postfix) with ESMTPSA id 5ED8A2EA308; Mon, 12 Oct 2020 10:50:30 -0400 (EDT) From: Mathieu Desnoyers To: David Ahern , Jakub Kicinski , "David S . Miller" , netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Mathieu Desnoyers Subject: [PATCH 2/3] ipv6/icmp: l3mdev: Perform icmp error route lookup on source device routing table (v2) Date: Mon, 12 Oct 2020 10:50:15 -0400 Message-Id: <20201012145016.2023-3-mathieu.desnoyers@efficios.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20201012145016.2023-1-mathieu.desnoyers@efficios.com> References: <20201012145016.2023-1-mathieu.desnoyers@efficios.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org As per RFC4443, the destination address field for ICMPv6 error messages is copied from the source address field of the invoking packet. In configurations with Virtual Routing and Forwarding tables, looking up which routing table to use for sending ICMPv6 error messages is currently done by using the destination net_device. If the source and destination interfaces are within separate VRFs, or one in the global routing table and the other in a VRF, looking up the source address of the invoking packet in the destination interface's routing table will fail if the destination interface's routing table contains no route to the invoking packet's source address. One observable effect of this issue is that traceroute6 does not work in the following cases: - Route leaking between global routing table and VRF - Route leaking between VRFs Use the source device routing table when sending ICMPv6 error messages. [ In the context of ipv4, it has been pointed out that a similar issue may exist with ICMP errors triggered when forwarding between network namespaces. It would be worthwhile to investigate whether ipv6 has similar issues, but is outside of the scope of this investigation. ] [ Testing shows that similar issues exist with ipv6 unreachable / fragmentation needed messages. However, investigation of this additional failure mode is beyond this investigation's scope. ] Link: https://tools.ietf.org/html/rfc4443 Signed-off-by: Mathieu Desnoyers Reviewed-by: David Ahern Cc: David Ahern Cc: Jakub Kicinski Cc: David S. Miller Cc: netdev@vger.kernel.org --- Changes since v1: - Introduce icmp6_get_route_lookup_dev. - Use skb->dev for routing table lookup, because it is guaranteed to be non-NULL. --- net/ipv6/icmp.c | 7 +++++-- net/ipv6/ip6_output.c | 2 -- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c index a4e4912ad607..91209a2760aa 100644 --- a/net/ipv6/icmp.c +++ b/net/ipv6/icmp.c @@ -501,8 +501,11 @@ void icmp6_send(struct sk_buff *skb, u8 type, u8 code, __u32 info, if (__ipv6_addr_needs_scope_id(addr_type)) { iif = icmp6_iif(skb); } else { - dst = skb_dst(skb); - iif = l3mdev_master_ifindex(dst ? dst->dev : skb->dev); + /* + * The source device is used for looking up which routing table + * to use for sending an ICMP error. + */ + iif = l3mdev_master_ifindex(skb->dev); } /* diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index c78e67d7747f..cd623068de53 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -468,8 +468,6 @@ int ip6_forward(struct sk_buff *skb) * check and decrement ttl */ if (hdr->hop_limit <= 1) { - /* Force OUTPUT device used as source address */ - skb->dev = dst->dev; icmpv6_send(skb, ICMPV6_TIME_EXCEED, ICMPV6_EXC_HOPLIMIT, 0); __IP6_INC_STATS(net, idev, IPSTATS_MIB_INHDRERRORS);